<--- Julius Caesar portrait bust, perhaps from his death mask

<--- Caesars tripartite Gaul

<--- Celtic coin depicting -- very primatively -- Commius, who is named on the reverse.  Caesar sent him to Britain to liaise with the British Celtic Atrebates, but he was arrested.  When released after Caesar arrived he achieved some authority among the British Atrebates, and later he became an enemy of Rome.

<--- Map of Caesars invasions
from https://en.wikipedia.org/wiki/Julius_Caesar%27s_invasions_of_Britain

The Wikipedia account of Caesar's two British expeditions is worth reading -- short and gives you the flavor.  Caesar's own account, running to 140 pages in English, is sometimes available in English either on the Internet or as a photo reprint of a 1916 translation (just for those of us who are obsessive/ compulsive.)

<--- Reprint of Caesar's account, out of stock at Amazon 0n 9 September 2025 but "more coming".

Julius Caesar's planning phase occupied much of 56 BC, and the invasion jump off should probably have been in late spring to early summer of 55 BC.  He built a substantial fleet ofships that he  was told could survive the dangerous "Ocean" between mainland Gaul and the land of the Britonic Celts, and he gathered as much intelligence as he could about Celtic strategy, tactics, military strength and organization.

But his intel sources were somewhat lacking, mostly consisting of mainland traders and entrepreneurs, Roman and otherwise, who were happy with the ways competition was already favoring themselves and wanting to keep their competitive edge rather than share the market with the political and military favorites, who always arrived with the baggage of the army and Roman civil government of occupation.  (It's still true today.)

From the Wikipedia account:
Caesar

By then, ambassadors from some of the British states, warned by merchants of the impending invasion, had arrived promising their submission. Caesar sent them back, along with his ally Commius, king of the Belgae Atrebates, to use their influence to win over as many other elites and tribes as possible.

He gathered a fleet consisting of eighty transport ships, sufficient to carry two legions (Legio VII and Legio X), and an unknown number of warships under a quaestor, at an unnamed port in the territory of the Morini, almost certainly Portus Itius (Saint-Omer). Another eighteen transports of cavalry were to sail from a different port, probably Ambleteuse. These ships may have been triremes or biremes, or may have been adapted from Venetic designs Caesar had seen previously, or may even have been requisitioned from the Veneti and other coastal tribes.

In late summer 55 BC, even though it was late in the campaigning season, Caesar decided to embark for Britain.  (TKW -->  Finally!!,  several months later than the optimal fighting season.  Or perhaps 10 months early, moved forward from 55 BC  for domestic Roman political publicity reasons.)

Caesar appears to have planned to sail straight across the channel from a Brittany port to the coast of Dover.  But when he did get across, he immediately realized that the beach was too
narrow and the cliffs were too high. Worst of all, the tops of the cliffs were packed with armed men -- and even armed and screaming women and even chanting and gesticulating Druids
with more ranks of the same behind them.



August 25, 55 BC, 9 AM

Caesar took pause ("until the ninth hour", about 3 PM) waiting at anchor for his supply ships to arrive from a different embarkation port, and, after convening a war council, he ordered his fleet to sail north-east to look for a better landing area.  He settled for a place many researchers think was probably near Ebbsfleet very near the end of the Kent peninsula. 

But that was, also, a much less than ideal place to run the ships on shore.  Caesar's infantry carriers were not flat-bottomed like modern landing craft, so they struck bottom in fairly deep water -- and the soldiers knew it.  The armored infantrymen bearing swords, shields, and iron tipped pilae didn't want to jump into what turned out to be neck deep water and wade ashore while
under fire from the Celtic mob that had matched, on land, their coastal progress by sea. 

Meanwhile, Celtic chariots were charging along the shingle. and Caesar's cavalry had not yet arrived to oppose them.  Caesar was still offshore and too far away to get rally his infantry, as he often had done before, but the the Aquilifer, the Eagle Standard Bearer, of the famous Tenth Legion, according to Caesar, jumped in shouting


The Aquilifer waded forward carrying the Tenth Legion Eagle followed by all of the infantry who feared deathless than the ignominy and shame that would thereafter haunt their legion or cause it to be dissolved.

<--- Tenth Legion Aquilifer leads the charge ashore, 25 August  55 BC. 

After what was probably little more than a skirmish, the Celts fled inland.  With no cavalry at hand, Caesar decided he could not safely pursue.  He took several days to consolidate the beach head using the time to pull his ships ashore.  After receiving embassies of the local British groups (identified as named "tribes", but sometimes named without known attribution). 

The southeast British "tribes" now sued for peace and promised hostages and tribute, most of which never were delivered.  The Brittany Gaul, Commius, Caesars co-conspiritor, was released and given a prestige position, but he eventually became an enemy of the Romans.

On the morning of the Romans' fourth day ashore, Caesar's 18
shiploads of horses and cavalrymen hove into view, but, before the equine reinforcement fleet could land and debark, a squall blew in, forcing the ships to turn about.  All 18 ships, all in danger of going awash, finally fled safely back to the Gaulish mainland coast, so Caesar fought on inland, without cavalry.

That same squall or one that followed closely behind destroyed some of Caesar's beached fleet and seriously damage all the rest.  More men were added to the beach-head detachment to start rebuilding/repairing the ships.

THe British Celts, on analyzing the new misfortunes of the Roman expedition, reneged on their previous diplomacy and surrenders and attacked Seventh Legion foragers.  Caesar immediately mobilized the rest of his forces, and then soundly defeated the "tribes" and retreated to his camp with most of his infantry unscathed. The ship repair project continued at the shoreline camp, and eventually all but 12 of the expedition's craft were made seaworthy -- if loosely fitted. 

Caesar, having completed a short (less than one month), armed reconnaissance, and having successfully out fought a few Celts in southeast Britain, then retreated and sailed back across "Ocean", to the mainland. 

Caesar, second invasion

The next year, 54 BC, after commissioning a new much bigger fleet (800 ships -- ten times the 55 BC fleet and built over winter in Gaul!!) with many flat-bottomed beachable ships (equipped with oars as well as sails), having assembled a much larger infantry force (five rather than two infantry legions with their auxiliaries) and figuring out how to deliver his cavalry to the battlefield, Caesar launched a second face-saving invasion.
According to Caesar, the White Cliff wall was still there in 54 BC, but strong currents and winds pushed his giant fleet past where he wanted to land -- at the same beach he had used in 55 BC.  Luckily Caesar, this time, had equippped his transports with oars in addition to sails, so the fleet rowed and struggled back to land at Pegwell Bay near Ebbsfleet in Kent.


The Celts ashore couldn't miss the Roman sea movements and, noting the size of the 800 ship fleet, wisely decided not to risk another beach battle like the one they lost the year before.  Caesar described their retreat without fighting into the hills above and beyond the beach. 

So the five legions landed unopposed. 

In 2017 archeologists reopened and expanded 2010 digs in the area and found the beach side "marching camp" that the legions immediately had built.  Artifacts were recovered including an easily recognized pilum point found a the bottom of a circumvallation trench providing the first solid evidence of the arrival point of Caesar's five legions. 


<--- Recovered Pilum point
The pilum was a Roman infantry soldier's initial javelin type weapon, thrown at approaching charging enemies to slow down or break the charge.  A pilum had a light wood shaft to which was fitted a thin and fairly long malleable iron shaft carrying a hardened iron  pyramid-shaped triangular head.  Some had an additional iron weight where the iron shaft was fitted to the wooden shaft to add momentum and therefore penetrating power into the target. 

The target was not, in fact, the enemy infantryman, but rather, his wooden shield.  After the hardened head went through the enemy shield the thin malleable iron shaft should twist or bend with the momentum of the charging enemy and others behind him forcing them to trip or at minimum climb over falling armed men whose shields would be in a twisted mass of spears. 

Roman infantrymen always lined up in multiple ranks and files when going into battle, many abreast and multiple (more than a few) rows deep behind ranks of shield walls.  Each trooper nominally carried two pilum spears into line, and, many across, whole ranks, were expected to volley their spears into the approaching enemies.  Up to six pilum volleys under command from the first three ranks would be practiced on the practice field to make sure they would always effectively slow or stop an enemy force.  The idea was to stop or slow the enemy so its line could nocking down and disabling troopers and spreadind chaos and panic

<---one of seven digs in the circumvalation trench around the marching fort.  Construction of a marching fort would begin as soon after troops arrived at a
place where they would encamp overnight, begining with a ditch (a fossa) surrounding the determined location.  The dirt from the ditch would be piled on the inner side of the ditch making what amounted to a rampart (a agger) on top of the agger would be mounted the two wooden planks that would be in charge of each marching infantry soldier -- or if landing from the sea, the planks would simply be unloaded from a supply transport.  All the dimensions and angles of the fortifications were standardized and would be known and built by all of the soldiers.  A defendable position would ideally be ready with temporary accommodations, galleys, and latrines/drainage by the first nightfall.

The remains of the standard ditches at Ebbsfleet were among the first things that helped the archeologists to identify the marching camp at Caesar's landings.

<--- Digging at several places along the suspected fossa ditch confirmed the standard construction angles of the inner and outer walls of the trench confirming the identity of the site as a "marching camp".
Artifacts (pilum point in particular) confirmed it belonged to
Caesar's landing area.

<---Part of Caesars Ebbsfleet more permanent fort.  Excavations in and around the area are not yet complete.

Some of the 800 ships that Caesar wrote were part of his fleet were likely supply ships.  The military's own ships probably were augmented by a large number of trading ships owned and manned by Romans and other entrepreneurs from elsewhere in the empire looking for financial and political gain. They probably were part of the claimed 800 ships.

Back in Gaul, unlike the year before, Caesar also had arranged for shipment of

March inland

Proposed map to the Stour river crossing in Kent where the first confrontation occured after Caesar returned from mending his storm tossed ships at the coastal fort.




Caesar then returned to the Stour crossing and found the Britons had massed their forces there. Cassivellaunus, a warlord from north of the Thames, had previously been at war with most of the British tribes. He had recently overthrown the king of the powerful Trinovantes and forced his son, Mandubracius, into exile. But now, facing invasion, the Britons had appointed Cassivellaunus to lead their combined forces. After several indecisive skirmishes, during which a Roman tribune, Quintus Laberius Durus, was killed, the Britons attacked a foraging party of three legions under Gaius Trebonius, but were repulsed and routed by the pursuing Roman cavalry.

Cassivellaunus realised he could not defeat Caesar in a pitched battle. Disbanding the majority of his force and relying on the mobility of his 4,000 chariots and superior knowledge of the terrain, he used guerrilla tactics to slow the Roman advance. By the time Caesar reached the Thames, the one fordable place available to him had been fortified with sharpened stakes, both on the shore and under the water, and the far bank was defended. Second century sources state that Caesar used a large war elephant, which was equipped with armour and carried archers and slingers in its tower, to put the defenders to flight. When this unknown creature entered the river, the Britons and their horses fled and the R

Caesar made no conquests in Britain, but his enthroning of Mandubracius marked the beginnings of a system of client kingdoms there, thus bringing the island into Rome's sphere of political influence.  Diplomatic and trading links developed further over the next century, opening up the possibility of permanent conquest, which was finally begun by Claudius in AD 43. In the words of Tacitus:

It was, in fact, the deified Julius who first of all Romans entered Britain with an army: he overawed the natives by a successful battle and made himself master of the coast; but it may be said that he revealed, rather than bequeathed, Britain to Rome.

Lucan's Pharsalia (II,572) makes the jibe that Caesar had:

...run away in terror from the Britons whom he had come to attack!

• Valerius Maximus's Memorable Words and Deeds (1st century AD) praises the bravery of Marcus Caesius Scaeva, a centurion under Caesar, who, having been deserted by his comrades, held his position alone against a horde of Britons on a small island, before finally swimming to safety.
• Polyaenus's 2nd-century Strategemata relates that, when Cassivellaunus was defending a river crossing against him, Caesar gained passage by the use of an armoured elephant, which terrified the Britons into fleeing.  This may be a confusion with Claudius's use of elephants during his conquest of Britain in AD 43.
• Orosius's 5th-century History Against the Pagans contains a brief account of Caesar's invasions, which makes an influential mistake: Quintus Laberius Durus, the tribune who died in Britain, is misnamed "Labienus", an error which is followed by all medieval British accounts.

• Bede's History of the English Church and People includes an account of Caesar's invasions. This account is taken almost word for word from Orosius, which suggests Bede read a copy of this work from the library at Monkwearmouth-Jarrow Priory which Benedict Biscop had brought from Rome itself.
• The 9th-century Historia Britonum attributed to Nennius gives a garbled account, in which Caesar invades three times, landing at the Thames Estuary rather than on a beach in Kent. His chief opponent is Dolobellus, proconsul of the British king Belinus, son of Minocannus. Caesar finally defeats the Britons at a place called Trinovantum.
• Henry of Huntingdon's 12th-century Historia Anglorum gives an account based on Bede and the Historia Britonum, and gives Caesar an inspirational speech to his troops.
• Geoffrey of Monmouth, in his History of the Kings of Britain, has Caesar invading Britain, and has Cassibelanus (i.e. Cassivellaunus) as Caesar's primary opponent, but otherwise differs from the historical record. As in the Historia Britonum, Caesar invades three times, not twice, landing at the Thames Estuary. His story is also largely based on Bede and the Historia Britonum, but is greatly expanded. Historical elements are modified – the stakes placed in the Thames by the Britons become anti-ship rather than anti-infantry and anti-cavalry devices  – and other elements, such as Cassibelanus's brother Nennius engaging in hand-to-hand combat with Caesar and stealing his sword, called Crocea Mors, are not known from any earlier source. Adaptations such as Wace's Roman de Brut, Layamon's Brut and the Welsh Bruts largely follow Geoffrey's story.
• The medieval Welsh Triads also refer to Caesar's invasions. Some of these references appear directly related to Geoffrey's account, but others allude to independent traditions: Caswallawn (Cassivellaunus) is said to have gone to Rome in search of his lover, Fflur, to have allowed Caesar to land in Britain in return for a horse called Meinlas, and pursued Caesar in a great fleet after he returned to Gaul.  .The 18th-century collection of Triads compiled by Iolo Morganwg contains expanded versions of these traditions.
• The 13th-century French work Li Fet des Romains contains an account of Caesar's invasions based partly on Caesar and partly on Geoffrey. It adds an explanation of how Caesar's soldiers overcame the stakes in the Thames – they tied wooden splints filled with sulphur around them, and burned them using Greek fire. It also identifies the standard-bearer of the 10th legion as Valerius Maximus's Scaeva.
• In the 14th-century French romance Perceforest Caesar, a precocious 21-year-old warrior, invades Britain because one of his knights, Luces, is in love with the wife of the king of England. Afterwards, a Briton called Orsus Bouchesuave takes a lance which Caesar used to kill his uncle, makes twelve iron styluses from the head, and, alongside Brutus, Cassius and other senators, uses them to stab Caesar to death.